An integrated circuit (IC) is a silicon chip that is as thin and small as a fingernail but is filled with tens of thousands of electronic components (such as transistors, diodes, resistors, and/or capacitors).
The electronic components are precisely connected to form logic gates or memory elements. The small electronic components and connections therebetween are all formed by making fine and complicated patterns in a plurality of layers of different materials.
When manufacturing semiconductor devices, several kinds of gases and chemicals are used in chemical vapor deposition (CVD) and etching processes, and apparatuses for the CVD and etching processes need to be maintained in a vacuum to prevent treatment subjects like wafers and substrates and/or parts of the apparatuses from being damaged or contaminated by external gases.